all-sky survey

An all-sky survey is a survey that makes no prior assumptions about the most likely directions
to search for a particular type of object, whether it be distant galaxies
or signals from an extraterrestrial civilization. An all-sky survey attempts
to sweep out entire sections of the sky as they appear from a given location.
Whereas instruments used in targeted
searches must be continuously moved to track selected objects, those
conducting all-sky surveys operate in what is called transit mode; that
is, they point in a fixed direction while the Earth rotates underneath them.
The majority of current SETI projects, such
as Project Argus, involve all-sky surveys.